According to some data, 80 percent of the population in the United States lives in urban areas. For those of you not counting (ahem...me), that's about 243 million people, give or take a million. These same people contributed to the 10.7 billion trips taken on public transportation in 2008 alone. In short: there are a lot of freakin' people who take municipal transit. If you are one of them, pay attention.

All too often, commuters forget one very important word in public transportation: public. There are innumerable ways in which this lack of consideration for one's fellow humans can become aggravating, offensive, or downright disturbing. I would take great pleasure in airing them all here*, but as this is CNET, I'll stick to tech-related grievances. What follows are some general guidelines for using your gadgets on transit (or in the general public, for that matter).

DON'T talk loudly on your cell phone when riding mass transit. In fact, if you can avoid it, don't talk on it at all. With the exception of some admittedly curious bystanders, most people don't want to be made privy to the ins and outs of your life...especially if the conversation is of a particularly private nature. No one wants to hear you berate your mom for calling too often (true story), and we certainly don't need to hear the words: "Yeah, so the doctor said you should probably get tested, too" (also a true story). OK, so maybe there's a bit of humor to that last one, but really, people? Have you no shame? Oh, and if it wasn't already clear from this, DON'T use your speakerphone, either.

I said...NO...TALKING!
Josh Miller/CNET

DO put your mobile on vibrate during your commute. This can be a tough one to remember, but it's a nice courtesy to other passengers. Most cell phone rings are at best annoying and at worst downright shrill. I'll be the first to admit I've been a culprit here. In my own little music bubble, I'm often completely oblivious to the fact that my phone might be ringing. I'm sure I've irritated my fair share of people.

DON'T listen to your music so loudly that others can clearly hear your music through those crappy headphones you're rocking. First off, that's terrible for your ears. Secondly, no one wants to be subjected to the distorted, tinny audio radiating from your head. Plus, we all listen to embarrassing music from time to time...do you really want everyone to know just how awful your taste is? (So many true stories in there it's not even funny--except that I listen to Don Henley, and that's pretty funny.)

Similarly, DON'T sing along with your MP3 player. We don't care how lovely your voice is: most of us just want to ride the bus (or train or subway) from point A to point B in peace. We have enough on our plates trying to avoid that seat that reeks of human urine, side-step that twitchy gentleman with the wild eyes, and hang on for dear life when our driver clearly has minimal control over the gas and brake pedals.

Look: you can be stylish and accommodating.

DO invest in a pair of sound-isolating earphones. Not only will you save your hearing, since this type of earbud lets you listen to music at lower volumes, but you'll keep your listening experience to yourself. Even better, you can block out external annoyances, such as those mentioned above. Loathe to stick things into your ears? Try a full-size, closed-back pair of headphones with minimal sound leakage, such as the Sony MDR-V700DJ or the Beats by Dr. Dre Headphones.

Also, DO use those earphones when you're playing a game on a handheld system, including the iPhone or iPod Touch. Many games have sound effects, and though these do add to the overall gaming experience, they're generally quite grating to anyone who's not immersed in the play.

DON'T view pornographic videos and photos in full view of your fellow passengers. Dude, do you really want to pop out your laptop and peruse pics of your naked girlfriend with a stranger sitting right next to you? How does she feel about that? (ABSOLUTELY TRUE STORY.) You would think this would be a no-brainer. Sadly, it is not.

Why do I feel like this list is way too short? Well, I didn't want to tire you out (or scare you away) this early in the game. But I'm sure there must be a thing or two I've missed, so by all means, please point these out in the comment section. Also, I will be continuing my call for suggestions throughout the tenure of this column, so be sure to e-mail those directly to me or add them below. Check back next week, and your own story might be featured here.